diff --git a/kernel/cpu.c b/kernel/cpu.c
index 077fde6fb953..ef1c565edc5d 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1964,6 +1964,9 @@ static ssize_t write_cpuhp_fail(struct device *dev,
 	if (ret)
 		return ret;
 
+	if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE)
+		return -EINVAL;
+
 	/*
 	 * Cannot fail STARTING/DYING callbacks.
 	 */
@@ -2339,6 +2342,9 @@ static int __init mitigations_parse_cmdline(char *arg)
 		cpu_mitigations = CPU_MITIGATIONS_AUTO;
 	else if (!strcmp(arg, "auto,nosmt"))
 		cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT;
+	else
+		pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n",
+			arg);
 
 	return 0;
 }